1. Field of the Invention
This invention relates generally to cutting devices, specifically to hand-held cutting devices, and more specifically, to hand-held cutting devices used for cutting explosive detonating cords.
2. Description of the Prior Art
Detonating cords that are used for setting off explosive charges are formed as lengths of packed explosive powder or crystals surrounded by a sheath or covering, such as nylon or rubber, that contains the explosive powder. The detonating cord may be supplied on a reel and cut to usable lengths. In utilizing the detonating cord, it is important that the ends of the cord are cleanly cut with the explosive core being level or flush with the surrounding sheath so that intimate contact can be made with explosive core of the detonating cord and the explosive being detonated.
Because of the characteristics of explosive detonating cord, conventional cutting devices used for cutting other materials cannot be used. Devices such as scissors or shears that apply a shearing and compressing action can damage the detonating cord, crushing and pinching the cord so that a clean cut is not achieved and creates a safety hazard to the operator.
One device that is often used for cutting detonating cord is a cap crimper. Although not intended to be used for such purposes, it is commonly used by those in the field who often find themselves without a sufficient tool for cutting the detonating cord. The cap crimper provides a less than adequate cutting device. The cap crimper is similar to a pliers. There is no sharp blade to provide a clean cut. The cap crimper tends to pinch the detonating cord, crushing the crystals forming the powdered explosive. This poses a safety hazard in itself. Further, this pinching action also tends to loosen the packed powdered explosive at the newly cut ends. This loose powder is usually lost so that the core explosive tends to be recessed from the end of the plastic or rubber sheath of the detonating cord. This creates an undesirable gap in the explosive of the detonating cord and the charge to be detonated.
An example of a prior art device that provides a fairly clean cut is shown in FIG. 1. The device 10 is formed from a solid piece of aluminum. A bore 12 is drilled through the length of the block and a transverse slot 14 intersecting the bore 12 is cut into the block. The detonating cord is then inserted through the bore 12. A razor blade (not shown) can then be inserted into the slot 14 and pressed downward so that the detonating cord is cut. This provides a fairly clean cut, but because the razor blades must be held in one's hands and because a fairly large force must be exerted on the blade in order to cut the detonating cord, there is a safety risk associated with this device. Further, the razor blades are routinely lost or misplaced.
What is therefore needed is a device for cutting detonating cords that provides a clean cut, without pinching or crushing of the explosive core, and that is safe and easy to use, and simple in design and construction.